Dental filling package

ABSTRACT

Direct dental filling materials utilizing a crosslinkable binder system and finely divided inorganic filler are packaged as two component systems with each of the two package components containing an intimate mix of unpolymerized resin binder and inorganic filler in the proportions in which they will be present in the cured dental filling. The contents of the two package components are essentially the same with the exception that one package component contains together with the resin binder and filler, an accelerator for the resin binder and the other package component contains a catalyst for the resin binder. In preparing a filling a portion of the contents of one package component is mixed with a portion of the content of the other package component. For color blending one of the package components may be prepared in different tints.

' Unite States Patent Lee, 11 et al.

[ Dec. 16, 1975 [54] DENTAL FILLING PACKAGE [75] Inventors: Henry Lawrence Lee, 11, San

Marino; Francis Fabian Smith, Los Angeles; Michael Lawrence Swartz, Encino, all of Calif.

[73] Assignee: Johnson & Johnson, New

Brunswick, NJ.

[22] Filed: Oct. 15, 1970 [21] Appl. No.: 81,156

I Related US. Application Data [63] Continuation of Ser. No. 736.950, June 14, 1968,

abandoned.

[52] US. Cl. 260/4253; 106/35; 260/4215 [51] Int. Cl. C08K 3/36 [58] Field of Search 260/41, 41 R, 42.53, 42.15;

[56] References Cited UNITED STATES PATENTS 3,066,112 11/1962 Bowen 260/41 3,302,410 2/1967 McLean 206/47 A X 3,825,518 7/1974 Foster et al 106/35 X 3,835,090 9/1974 Garder et a1 106/35 X Primary ExaminerDonald E. Czaja Assistant ExaminerS. M. Person [5 7 ABSTRACT Direct dental filling materials utilizing a crosslinkable binder system and finely divided inorganic filler are packaged as two component systems with each of the two package components containing an intimate mix of unpolymerized resin binder and inorganic filler in the proportions in which they will be present in the cured dental filling. The contents of the two package components are essentially the same with the exception that one package component contains together with the resin binder and filler, an accelerator for the resin binder and the other package component contains a catalyst for the resin binder. In preparing a fill ing a portion of the contents of one package compo nent is mixed with a portion of the content of the other package component. For color blending one of the package components may be prepared in different tints.

11 Claims, N0 Drawings contained reactive liquid diluent monomer, package DENTAL FILLING PACKAGE component (3) contained the reactive liquid diluent This application is a continuation of our copending monomer together with an activator for the system, and application Ser. No. 736,950 filed June 14, 1968, entipackage component (4) contained the catalyst, bentled Dental Filling Package, and now abandoned. 5 zoyl peroxide.

When using this prepackaged system in making his BRIEF DESCRIPTION OF THE INVENTION fillings it was first necessary that the dentist activate a Direct filling materials utilizing a finely divided filler portion of his diluent monomer. This was done by takand a resin binder have heretofore been proposed. ing a small amount of catalyst from package compo- Such a direct filling material is described, for example, nent (4) and adding it to some reactive diluent monoin Bowen U.S. Pat. No. 3,066,l 12. One of the difficulmer taken from package component (2). The activated ties in marketing such direct filling materials is the monomer so prepared because of its short storage life problem of packaging. in any filling system utilizing a of about thirty days, had to be prepared periodically by polymerizable organic binder and finely divided inorthe dentist. When preparing the filling the dentist then ganic filler it is necessary for the dentist to blend tomixed together premeasured proportions of the paste gether the components just prior to placing the filling in from package component l the catalyzed reactive the tooth cavity. Accordingly, any packaging systems diluent monomer which had been previously prepared for fillings of this type should be such as to reduce the by the dentist and a portion of the reactive monomer chance of error on the dentists part with respect to the containing activator from package component (3). As proper proportioning of ingredients in preparing the the ratio of BIS-GMA to reactive diluent monomer is filling. It should also simplify the mixing procedure, as critical for obtaining the maximum binder strength as the time permitted for mixing and inserting the dental well as is the ratio of filler to binder resin, substantial filling material is limited. Furthermore, in packaging care had to be exercised by the dentist in order to be dental filling materials the ingredients must be so packsure that proper proportions were admixed according aged that reaction and deterioration is minimized over to the directions contained with the prepackaged sysrelatively long periods of storage otherwise the ingreditem.

ents will have been found to have deteriorated by the The problems confronting a dentist in preparing a time the dentist is ready to use the same. filling using such a prepackaged system can be readily in direct filling systems such as described in Bowen seen. It is necessary for him to remember to keep on U.S. Pat. No. 3,066,l 12 the binder system is composed hand a fresh batch of catalyzed reactive diluent monoof the monomer mer, to carefully measure out the proportional parts monomer H Hg H H H (I) HCH 0 HCH H H l H l H HC C-C-O-C-C-C-O- C- C D .0-C-C-CO-C--=CH H H H H H a H l 3 H 0 HCH H O hereinafter referred to as BIS-GMA, admixed with from the different containers to obtain the proper ratio other active monomers referred to by Bowen as reacof monomers and the proper ratio of binder to inortive diluents. The binder resin system is activated ganic filler and to completely blend the mixture. All of through the inclusion of both an activator and a catathis had to be done immediately prior to placing the lyst. In marketing such systems it has heretofore been filling in the cavity. The blending must be done rapidly the practice to prepare a paste of the BIS-GMA monootherwise the binder would polymerize to too hard a mer and the finely divided filler, as a paste is much mass prior to the dentist being able to place the easier for the dentist to handle when making the final blended filling in the tooth and work it into the cavity.

mix, than is a dry powder such as the filler itself would Blending must also be uniform otherwise the filling will present. Portions of the other active monomers have vary in consistency depending on the ratio of binder to heretofore been packaged separately from the BIS- filler found in the final filling. Furthermore, consider- GMA in order to avoid premature reaction. This packable care must be exercised in measuring out the aging has been thought necessary in order to obtain the proper quantities from the respective package compoextended life required for any such prepackaged sysnents. All of these factors place a substantial strain on tern. Asaresult, although stable prepackaged materials the dentist preparing the filling with the result that for making fillings of the type described in Bowen Pat. dental fillings so prepared may vary substantially with No. 3,066,112 have been made commercially availthe best results not being obtained. Also, substantial able, stability has been obtained by careful separation waste is encountered as it is extremely difficult to meaof many of the component parts to avoid prepolymerisure accurately the small quantities needed to fill one zation with the result that the package made available or two teeth with the result that substantially more to the dentist contained four separate package compofilling material is blended than is actually needed. nents. It has been discovered that in dental restorativesys- Of these package components, package component terns such as that of Bowen Pat. No. 3,066,l 12 where (1) contained a paste comprising a mixture of BIS- an inorganic filler is present in amounts substantially GMA and inorganic filler, package component (2) greater than the binder resin and an activator and catalyst are employed that the monomers comprising the binder resin can all be premixed with the finely divided inorganic filler and be kept in this premixed state for many months even in the presence of a catalyst or an activator without undue deterioration of the binder system occurring. It has further been discovered that where the catalyst for the system is included in one premixed lot of binder and filler and the activator for the system is included in the other premixed lot of binder and filler that when portions of the lot containing the catalyst and portions of the lot containing the activator are then blended, excellent polymerization is obtained. As a result, when packaging is done in accordance with the present invention the dentist is supplied with a two component package system. All critical blending has been predone by the manufacturer. As it is only necesary to have sufficient amounts of catalyst and activator present to initiate polymerization, not even the proportionate amount taken and blended from the two package components is critical. As a result the dentist can take quite small amounts for blending thus avoiding waste. All critical blending is accurate as it is done by the manufacturer with the result that more consistent fillings are obtained. Furthermore, time for mixing, on the part of the dentist, is substantially reduced.

Direct filling mterials of the type utilizing a binder system composed of unreacted monomers, an inorganic filler, and an activator andcataylst, particularly of the type where one of the reactive monomers is a his phenol A containing monomer are packaged in a two component package wherein each of the package components contains a mixture of the unpolymerized resin binder and the inorganic filler in substantially the proportions in which they will be present in the final cured filling and one of the package components contains, together with the premixed nonpolymerized binder and filler, an accelerator for the binder system while the other package component contains together with the premixed nonpolymerized binder and inorganic filler a catalyst for the binder system.

As the binder and inorganic filler are premixed in the proper ratio and the catalyst and activator serve to initiate the reaction but are not highly critical with respect to amounts'present, the dental filling can be readily prepared by taking approximately equal portions of each of the two components of the package and blending together. Also, the packaging system is ideally suited for providing the dentist with several base shades which he then can blend to obtain the particular shade which he may desire for the filling. One of the package components, where tinting is desired, is made up in several of the basic shades. The dentist then blends various proportions of the basic shades together to get the shade desired and then blends this mix, which is still unreactive, with a substantially equal portion of the other package components which contain the missing catalyst or activator depending on which was used in preparing the various basic shade mixes.

DETAILED DESCRIPTION OF THE INVENTION In direct filling systems wherein the filling consists essentially of a finely divided inorganic filler bonded together by a polymerized resin binder substantial difficulty has been encountered in prepackaging the necessary ingredients to make the filling in such a form that they can be easily and conveniently handled by the dentist and will not deteriorate prior to use. A filling material of this type is well illustrated by the filling system described by Bowen in his U.S. Pat. No. 3,066,112. The filling system of Bowen utilizes as a binder system a monomer having a bis phenol A backbone having the structure and terminal acrylate group. Bowen suggests than an active monomer be added as a diluent to control the viscosity of his bis phenol A backbone monomer. One of the advantages of using a monomer system of this type is the large amount of finely divided inorganic filler with which the same can be blended in making a filling. Inorganic filler can be blended in with the binder resin in amounts as high as 78 percent by weight of the dental filling material. Substantial difficulty has, however, been encountered in the packaging of the necessary ingredients for making fillings of this general type, that is, a difficulty in prepackaging in such manner that the work and responsibility on the part of the dentist for handling and obtaining accurate blend is substantially reduced.

It has now been discovered that where the ratio of finely divided inorganic filler to resin binder is such that the filler is present in amounts of at least 65 percent by weight of the total mix that the unpolymerized components of the binder resin will remain unpolymerized for extended periods of time. This permits the binder resin to be premixed with the filler in substantially the proportions in which the binder resin and filler will occur in the cured filling with the same remaining stable and unpolymerized for many months. It has further been discovered that such premixed inorganic filler and unpolymerized resin binder can have blended therewith either the activator for the system or the catalyst for the system and still remain in an unpolymerized state for many months. However, when a portion of the premixed resin and inorganic filler containing the activator is blended with a portion of the premixed binder and inorganic filler containing a catalyst for the system, the binder then polymerizes and cross-links to give a strong, useful filling.

Although the packaging system of the present invention may be used for the prepackaging of any cement formed of an inorganic filler and binder therefor where the inorganic filler is present in amounts at least equal to the weight of the unpolymerized binder, the same is particularly suitable for the prepackaging of cement systems suitable for filling teeth utilizing as the primary binder monomer or one of the primary binder monomers a bis phenol A backbone monomer with terminal acrylic groups. As the dental filling materials described in Bowen Pat. No. 3,066,1 12 are good examples of filling materials of this type, the same will be used in more specifically describing the practice of the present invention.

The dental filling system of Bowen Pat. No. 3,066,112 comprises in essence a finely divided inorganic filler bonded together by a cross-linked resin binder. The ingredients in unpolymerized system which when blended together on polymerization give the aforementioned filling are the binder system, an activator for the binder system, a catalyst for the binder system, and a finely divided inorganic filler.

THE BINDER SYSTEM H HCH g l H I this particular monomer is hereinafter referred to as BlS-GMA. The BIS-GMA may be the only bis phenol A backbone containing monomer in the system or the system may be modified through the inclusion of other bis phenol A backbone monomers.

A bis phenol A backbone monomer is the primary monomer in the binder system. BIS-GMA, the his phenol A backbone monomer of Bowen, may be prepared, for example, by any of the methods described in U.S. Pat. No. 3,066,112. The viscosity of the his phenol A backbone monomer, which may be a mixture of his phenol A backbone monomers, is adjusted to a medium viscosity syrup by addition of reactive diluent monomers such as methyl methacrylate and the glycol dimethacrylate such as ethylene glycol dimethacrylate through tetraethylene glycol dimethacrylate with the preferred reactive diluent monomer being triethylene glycol dimethacrylate. Other suitable reactive diluent monomers may be used. The bis phenol A backbone monomer will generally comprise about 80 percent or more of the binder system with the active diluent monomer or monomers making up the rest of the interpolymerizable monomers present.

In order to obtain reasonably rapid curing an activator is used for the binder system. Suitable activators are, for example, N,N-dimethyl-para-toluidine and para-toluenesulfinic acid. However, the activator is not limited to these particular ones, but other amine activators may be used. Also, in order to initiate the polymerization a suitable catalyst is employed, such as benzoyl peroxide. Other activators are described, for example, in US. Pat. No. 2,558,139. The activator reacts with the peroxide catalyst to produce free radicals. The amount of activator will depend on the particular activator used and the working time needed prior to the commencement of hardening after the binder and finely divided filler have been mixed ands catalyzed. The activator will generally be present in amounts of about 0.1 to 2 percent by weight of the reactive monomers in the binder system. Where a catalyst such as benzoyl peroxide is used it would generally be present in amounts of about 1 to 2 percent by weight of the binder system. The activator and catalyst are not considered as a part of the binder system as the term is used herein, as the same are used to catalyze and control the rate of polymerization of the monomers which interact to give the final cured binder in the dental filling.

THE FILLER The filler may be any finely divided solid which when dispersed through the binder system will give improved structural strength when the binder system is polymer- H H Him 0 H I H r t -Q 3 H I I H 0 HgH 1-1 0 ized into a cured resin. The best fillers are finely divided inorganic materials such as fused silica, aluminum oxide, crystalline quartz, small glass beads and the like. The finely divided filler has a particle size generally in the range of about 2 to with the preferred size being within the range of about 5 to 75 microns. The best results are obtained where the inorganic filler is treated with a keying agent to improve the bond between the organic polymer binder and the surface of the finely divided filler particles. Keying agents which have been found highly suitable are the ethylenically unsaturated organosilane finishing or keying agents where the filler is fused silica, glass, aluminum oxide, or crystalline quartz and the binder system is of the type described. The finely divided filler may be treated with the keying agent, for example, in the manner described .in US. Pat. No. 3,066,! 12 wherein an aqueous solution of tris( 2-methoxy ethoxy) vinyl silane is catalyzed with sodium hydroxide to give a pH of 9.3 to 9.8, and the filler treated with this solution, for example, one-half percent of the silane being used per weight of fused quartz. A slurry so formed is dried at about C. and cooled.

The binder system is then blended with the inert filler into a paste comprising from about 65 to 75 percent by weight filler with the remainder being the binder system. The binder system, as previously indicated, is the blend of active monomers which later polymerize to give the cured organic polymer forming the binder in the filling. In the preferred systems the inert filler is present in amounts of at least 70 percent. The paste comprising the binder system and the finely divided filler is divided into substantially equal portions and to one portion is added an accelerator for the binder system while to the other portion is added a catalyst for the binder system. Although as described the catalyst and accelerator areadded after the paste of binder system and finely divided filler has been prepared, one could add the catalyst and the accelerator during the blending of the finely divided filler and binder system the same being proportioned prior to blending rather than afterwards.

In order to simplify the description the binder system inert filler paste containing the activator will hereinafter be called package component A and the blend of binder system and finely divided filler containing the catalyst will be referred to as package component B. Package component A and package component B are both found to be quite stable over many months storage under normal room conditions. This is quite surprising when it is considered that if the catalyst is added to the binder system, polymerization of the binder system will be found to occur after a few days. Also, the binder system itself even without the addition of the catalyst where it contains a mixture of active monomers is found to be unstable and tend to polymerize, particularly where such active monomer diluents as methyl methacrylate are present. Thus, it is quite surprising that the binder system-inorganic filler paste withthe catalyst present is stable and may still be used after 7 many months.

Package component A and package component B may be placed in any type of container formed of a material that is inert to the system. Thus the container may be a tube formed of such materials as chemically inert plastics such as polyethylene, polypropylene, tinlined metal and the like or small dishes formed of such materials, as well as glass containers and the like. It is generally preferred to include in the paste small amounts of ultraviolet light absorbers and inhibitors to further assure stability of the system. A suitable inhibitor, for example, is butylated hydroxy-toluene which may be added in amounts of .01 to .03 percent by weight based on the total binder system filler paste and ultraviolet absorbers such, for example, as Z-hydroxy- 4-methoxy-benzophenone in amounts of .2 to .3 percent based on the weight of the binder system finely divided filler paste. Also, in packaging the pastes of package component A and package component B in glass or other light-permeable containers, it is generally desirable to have the same tinted to exclude ultraviolet light.

It is found that in some instances some separation between the binder system and the finely divided filler may occur after several months storage. Where such separation does occur it is also found, particularly in package component B, that some polymerization may also occur in the liquid phase of the separation. Where such separation occurs, the contents can be again mixed and are found to be still suitable for preparing dental fillings. However, this is undesirable as it requires a periodic remixing by the dentist, and as previously indicated, there is also the danger of some polymerization occurring in the liquid phase if permitted to stand too long. It has been discovered that this slight separation of binder system from the finely divided filler can be prevented if a small amount of submicron particles are added. Thus, where the filler is aluminum oxide having a particle size of to 50 microns, in the preferred practice of the present invention 1 to 4 percent by weight of submicron floculated silica are added. Interestingly, no evidence of this separation or settling is found to occur in smaller masses, 20 to 30 grams, of either package component A or package component B even after storage as much as 3 months at room temperature. However, with larger masses such, for example, as more than 50 grams of fused alumina in the particular mass some settling, as previously indicated, has been found to occur. The submicron silica may be mixed with the resin binder before the same is mixed with the fused alumina or other finely divided filler. Thus, for example, the addition of 2 percent hydrophobic submicron silica to a resin binder system blended with 70 percent by weight fused alumina gave a consistency in the final formula which was little changed from a formula identical with the exception that the hydrophobic submicron silica was not added.

Although the presence of the submicron silica substantially eliminated the settling, its incorporation was found to have no adverse effects on the properties of the system with respect to curing and on the properties of the finally cured material.

In preparing the dental filling substantially equal portions of package component A and package component B are blended together. Polymerization is found to occur in about 1 to 3 minutes depending on the particular activator and amount present. The same results are obtained even though the proportions of package component A and package component B used in the mixture are varied to as much as 2 parts of one to the other, thus indicating the noncriticality of the proportionate amounts used.

As the binder is colorless and as most of the preferred filler materials are white, it may be desirable to include some pigment. However, unless the dentist is himself able to blend to the particular shade in which he is interested, pigmented filling mixes are not too desirable. It has heretofore been proposed to use various blends of inert filler to optically match the tooth structure so as to permit some of the underlying color of the tooth to pass through. This may by achieved by selecting the proper blend of glass beads and quartz to give the proper light index to the set filling material. The present package system, however, blends itself ideally to where pigmented fillings are desired as either package component A or package component B can be put up in several separate containers each having a different base color shade thus, as base color shades, one may use brown, gray, yellow, universal and unpigmented. The dentist then in preparing the filling would take small proportions of different ones of the base colored package components A and blend the same to obtain the desired shade which he was seeking. There would be no pressure on the dentist with respect to the binder setting while he was selecting and doing his blending as all of the material blended would be package component A. If desired, the basic color shades could be prepared in package component B rather than A. However, whichever one is selected that should be the one which contains all of the pigmented mixes so that the same can be blended as previously indicated without polymerization. After the desired shade is obtained then the blended material is admixed with the binder resin-inorganic filler mix of the other component package.

The practice of the invention is further illustrated by the following Example which is given for purposes of illustration only, the invention not being limited thereto.

EXAMPLE A binder system is prepared by blending together 95 parts BlS-GMA and 17 parts triethylene glycol dimethacrylate. Fourteen parts by weight of submicron silica are blended in with the binder system. The binder system so prepared containing the submicron silica is then divided into two equal parts. One part is then blended with fused alumina having a particle size range of 10-15 microns in the proportion of 25 parts by weight binder to parts by weight of fused alumina. Two parts by weight of benzoyl peroxide are added to the mix and blended therein.

The remaining portion of binder system containing the submicron silica is divided into five parts. Organic dyes are then added to give one part of brown tint, one a gray, one a yellow, one a universal tint and the other is left unpigmented. Prior to adding the dye an activator N,N-dimethyl-p-toluidine is added to the binder mix prior to dividing into the five parts as above described. The activator is added in an amount of 2 parts activator to 98 parts by weight total monomer present. Each of the pigmented and unpigmented portions of the monomer mix are then blended with the fused alumina in the proportion of 25 parts by weight monomer to 75 parts by weight fused alumina. The mix prepared with the catalyst benzoyl peroxide is referred to as package component B and the mixes prepared with the activator are referred to as package component A. The color blending is first done by using small amounts of differ ent colors from the package components A. Thus, in preparing a filling having a slightly warm tint, a small amount of brown paste from a package component A (brown) is blended with a small amount of paste from package component A (gray) and paste from a package component A (neutral). If it is found that a slight bit of yellow is needed to more closely approach the shade desired, a small amount of yellow from package component A (yellow) is then added, the yellow being added in the amounts needed to reach the desired shade. The mix so obtained having the desired shade is then blended with an approximately equal proportion of material taken from package component B. The two pastes are mixed by spatula on a mixing slab. The mix so obtained is placed in a preprepared cavity of a tooth where it hardens in approximately 2 minutes from the time that the material from package components A is blended with the material from package component B.

The contents of package component A and package component B are found to still be active and exhibit no separation after several months storage under ordinary room conditions.

Particular embodiments of the invention have been used to illustrate the same. The invention, however, is not limited to these specific embodiments. In view of the foregoing disclosure, variations and modifications thereof will be apparent, and it is intended to include within the invention all such variations and modifications except as do not come within the scope of the appended claims.

Having thus described our invention, we claim:

1. A method of filling a tooth comprising the steps of:

a. providing a first quantity of paste-like material consisting essentially of: a premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; a finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said paste-like material; and a free radical generating catalyst for said binder system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system;

b. providing a second quantity of paste-like material consisting essentially of: substantially the same premixed unpolymerized resin binder system which is in said first quantity of material; a finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said second quantity of paste-like material; and an activator for said catalyst to cause the aforesaid generation of free radicals in sufficient quantities to produce relatively rapid polymerization of said binder system; 7 extracting from each of said quantities of material approximately equal amounts of the same sufficient to effect the desired tooth restoration;

. mixing said extracted quantities so that said activator of said second quantity of material reacts with said catalyst of said first quantity of material causing the generation of sufficient free radicials to inititate relatively rapid polymerization of said resin binder system; and

. promptly filling a tooth with said mixture before it hardens due to polymerization so that after said mixture is in a tooth it will harden in a known and substantially uniform time to form a hard dental filling.

2. A method of producing a hard dental filling comprising the steps of:

a. taking a quantity of paste-like material consisting essentially of: pre-mixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said materal; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system;

b. mixing an activator which is reactive with said catalyst to cause. generation of free radicals in sufficient quantities to cause relatively rapid polymerization of said system into said quantity of paste-like material so as to initiate relatively rapid polymerization of said system, said activator being added in the form of a paste-like composition in which the activator is substantially uniformly dispersed throughout a mixture of unpolymerized resin binder system and finely divided filler, said activator when mixed in such form resulting in a more uniform initiation of polymerization throughout the binder system and a dental filling of greater initial hardness when said mixture is placed in a tooth immediately after preparation.

3. A storable and activatable paste-like material for use in producing a hard dental filling material consisting essentially of: an intimate mix of resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said material; and a free radical generating catalyst which when activated will generate free radicals in sufficient quantity to produce relatively rapid polymerization of said system and which material will remain substantially unpolymerized and ready to be activated for a period of months.

4. A storable and activatable paste-like material for use in producing a hard dental filling material consisting essentially of: an intimate mix of resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler selected from the group consisting of fused silica, aluminum oxide, crystalline quartz and glass beads, said filler constituting at least 65 percent by weight of said material; and a free radical generating catalyst which when activated will generate free radicals in sufficient quantity to produce relatively rapid polymerization of said system and which material will remain substantially unpolymerized and ready to be activated for a period of months.

5. A storable and activatable paste-like material for use in producing a hard dental filling material consisting essentially of: an intimate mix of resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finelydivided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said material, in which a small portion of said filler is replaced by an amount of hydrophobic submicron silica sufficient to substantially eliminate separation between said binder system and filler; and a free radical generating catalyst which when activated will generate free radicals in sufficient quantity to produce relatively rapid polymerization of said system and which material will remain substantially unpolymerized and ready to be activated for a period of months.

6. A storable and activatable paste-like material for use in producing a hard dental filling material consisting essentially of: an intimate mix of resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups and which resin binder system includes at least 85 percent by weight of bis phenol A backbone monomer; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said material; and a free radical generating catalyst which when activated will generate free radicals in sufficient quantity to produce relatively rapid polymerization of said system and which material will remain substantially unpolymerized and ready to be activated for a period of months. 7. A manufacturespecifically for a dentist to use in producing hard dental fillings in a substantially uniform manner, said manufacture being composed of two paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of materials to produce a dental filling to be made, the material in one of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said paste-like material; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of: substantially the same premixed unpolymerized resin binder system as in said first container; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of the material in said other container; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity to produce relatively rapid polymerization of said system; the mixture of materials extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known andsubstantially uniform time to produce a hard dental filling after being placed in a tooth.

, 8. A manufacture specifically for a dentist to use in producinng hard dental fillings in a substantially uniform manner, said manufacture being composed of two paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of material to produce a dental filling to be made, the material in one of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer havinga central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said paste-like material; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of substantially the same premixed unpolymerized resin binder system as in said first container; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of the material in said other container; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity to produce relatively rapid polymerization of said system; the mixture of materials extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known and substantially uniform time to produce a hard dental filling after being placed in a tooth; and the quantity of material containing the activator being colored so that said mixture will substantially match the color of the tooth in which it is to be placed.

9. A manufacture specifically for a dentist to use in producing hard dental fillings in a substantially uniform manner, said manufacture being composed of two paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of material to produce a dental filling to be made, the mateial in one of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler selected from the group consisting of fused silica, aluminum oxide, crystalline quartz and glass beads, said filler constituting at least 65 percent by weight of said paste-like material; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of: substantially the same premixed unpolymerized resin binder system a. in said first container; finely-divided, organosilane keying agent-treated, inorganic filler selected from the group consisting of filsed silica, aluminum oxide, crystalline quartz and glass beads, said filler constituting at least-65 percent by weight of the material in said other container; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity to produce relatively rapid polymerization of said system; the mixture of material extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known and substantially uniform time to produce a hard dental filling after being placed in a tooth; and the quantity of material containing the activator being colored so that said mixture will substantially match the color of the tooth in which it is to be placed.

10. A manufacture specifically for a dentist to use in producing hard dental fillings in a substantially uniform manner, said manufacture being composed of two paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of materials to produce a dental filling to be made, the material in one of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said paste-like material, in which a small portion of said filler is replaced by an amount of hydrophobic submicron silica sufficient to substantially eliminate separation between said binder system and said filler; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of: substantially the same premixed unpolymerized resin binder system as in said first containers; finely-divided, organosilane keying agenttreated, inorganic filler constituting at least 65 percent by weight of the material in said other container in which a small portion of said filler is replaced by an amount of hydrophobic submicron silica sufficient to substantially eliminate separation between said binder system and said filler; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity of produce relatively rapid polymerization of said system, the mixture of materials extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known and substantially uniform time to produce a hard dental filling after being placed in a tooth.

11. A manufacture specifically for a dentist to use in producing hard dental fillings in a substantially uniform manner, said manufacture being composed of two 14 paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of material to produce a dental filling to be made, the material in one of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups and in which said resin binder system includes at least percent by weight of his phenol A backbone monomer; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said paste-like material; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of: substantially the same premixed unpolymerized resin binder system as in said first container; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of the material in said other container; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity to produce relatively rapid polymerization of said system, the mixture of materials extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known and substantially uniform time to produce a hard dental filling after being placed in a tooth.

UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF GORRECTION F'AILNT NO. 3,926,906

DATED December 16, 1975 lN\/ ENTOR(S) I Henry Lawrence Lee, II et al It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 6, Line 59 through Column 7, Line 1, delete the three sentences-- This is quite surprising when it is considered that if the catalyst is added to the binder system, polymerization of the binder system will be found to occur after a few days. Also, the

. binder system itself even without the addition of the catalyst where it contains a mixture of active monomers is found 6 be unstable and tend to polymerize, particularly where such active monomer diluents I as methyl methacrylate are present. Thus, "it is quitesurprising that the binder system-inorganic filler paste with the catalyst present is stable and may still be used after many months.

' Signed and Scaled this I Twenty-second D 3) of February 1977 [SEAL] Arrest: I

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner oj'Parenrs and Trademarks 

1. A METHOD OF FILLING A TOOTH COMPRISING THE STEPS OF: A. PROVIDING A FIRST QUANTITY OF PASTE-LIKE MATERIAL CONSISTING ESENTIALLY OF A PREMIXED UNPOLYMERIZED ESIN BINDER SYSTEM CONTAINING ACTIVE POLYFUNCTIONAL MONOMER HAVING A CENTRAL PORTION WHICH CONTAINS AT LEAST ONE AROMAATIC RING AND AT LEAST TWO ACRYLIC END GROUPS, A FINELY-DIVIDED ORGANOSILANE KEYING AGENT-TREATED INORGANIC FILLER CONSTITUTING AT LEAST 65 PERCENT BY WEIGHT OF SAID PASTE-LIKE MATERIAL; AND A FREE RADICAL GENERATING CATAALYST FOR SAID BINDER SYSTEM IN WHICH THE FREE RADICALS WHEN GENERATED IN SUFFICIENT QUANTITIES WILL PRODUCE RELATIVELY RAPID POLYMERIZATION OF SAID SYSTEM; B. PROVIDING A SECOND QUANTITY OF PASTE-LIKE MATERIAL CONSISTING ESSENTIALLY OF: SUBSTANTIALLY THE SAME PREMIXED UNPOLYMERIZED RESIN BINDER SYSTEM WHICH IS IN SAID FIRST QUANTITY OF MATERIAL, A FINELY-DIVIDED ORGANOSILANE KEYING AGENT-TREATED, INORGANIC FILLER CONSITUTING AT LEAST 65 PERCENT BY WEIGHT OF SAID SECOND QUANTITY OF PASTE-LIKE MATERIAL; AND AN ACTAIVATOR FOR SAID CATALYST TO CAUSE THE AFORESAID GENERATION OF FREE RADICALS IS SUFFICIENT QUANTITIES TO PRODUCE RELATIVELY RAPID POLYMERIZATION OF SAID BINDER SYSTEM; C. EXTRACTING FROM EACH OF SAID QUANTITIES OF MATERIAL APPROXIMATELY EQUAL AMOUNTS OF THE SAME SUFFICIENT TO EFFECT THE DESIRED TOOTH RESTORATION; D. MIXING SAID EXTRACTED QUANTITIES SO THAT SAID ACTIVATOR OF SAID SECOND QUANTITY OF MATERIAL REACTS WITH SAID CATALYST OF SAID FIRST QUANTITY OF MATERIAL CAUSING THE GENERATION OF SUFFICIENT FREE RADICALS TO INITIATE RELATIVELY RAPIDF POLYMERIZATION OF SAID RESIN BINDER SYSTEM; AND E. PROMPTLY FILLING A TOOTH WITH SAID MIXTURE BEFORE IT HARDENS DUE TO POLYMERIZATION SO THAT AFTER SAID MIXTURE IS IN A TOOTH IT WILL HARDEN IN A KNOWN AND SUBSTANTIALLY UNIFORM TIME TO FORM A HARD DENTAL FILLING.
 2. A method of producing a hard dental filling comprising the steps of: a. taking a quantity of paste-like material consisting essentially of: pre-mixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said materal; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; b. mixing an activator which is reactive with said catalyst to cause generation of free radIcals in sufficient quantities to cause relatively rapid polymerization of said system into said quantity of paste-like material so as to initiate relatively rapid polymerization of said system, said activator being added in the form of a paste-like composition in which the activator is substantially uniformly dispersed throughout a mixture of unpolymerized resin binder system and finely divided filler, said activator when mixed in such form resulting in a more uniform initiation of polymerization throughout the binder system and a dental filling of greater initial hardness when said mixture is placed in a tooth immediately after preparation.
 3. A storable and activatable paste-like material for use in producing a hard dental filling material consisting essentially of: an intimate mix of resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said material; and a free radical generating catalyst which when activated will generate free radicals in sufficient quantity to produce relatively rapid polymerization of said system and which material will remain substantially unpolymerized and ready to be activated for a period of months.
 4. A storable and activatable paste-like material for use in producing a hard dental filling material consisting essentially of: an intimate mix of resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler selected from the group consisting of fused silica, aluminum oxide, crystalline quartz and glass beads, said filler constituting at least 65 percent by weight of said material; and a free radical generating catalyst which when activated will generate free radicals in sufficient quantity to produce relatively rapid polymerization of said system and which material will remain substantially unpolymerized and ready to be activated for a period of months.
 5. A storable and activatable paste-like material for use in producing a hard dental filling material consisting essentially of: an intimate mix of resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said material, in which a small portion of said filler is replaced by an amount of hydrophobic submicron silica sufficient to substantially eliminate separation between said binder system and filler; and a free radical generating catalyst which when activated will generate free radicals in sufficient quantity to produce relatively rapid polymerization of said system and which material will remain substantially unpolymerized and ready to be activated for a period of months.
 6. A storable and activatable paste-like material for use in producing a hard dental filling material consisting essentially of: an intimate mix of resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups and which resin binder system includes at least 85 percent by weight of bis phenol A backbone monomer; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said material; and a free radical generating catalyst which when activated will generate free radicals in sufficient quantity to produce relatively rapid polymerization of said system and which material will remain substantially unpolymerized and ready to be activated for a period of months.
 7. A manufacture specifically for a dentist to use in produciNg hard dental fillings in a substantially uniform manner, said manufacture being composed of two paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of materials to produce a dental filling to be made, the material in one of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said paste-like material; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of: substantially the same premixed unpolymerized resin binder system as in said first container; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of the material in said other container; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity to produce relatively rapid polymerization of said system; the mixture of materials extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known and substantially uniform time to produce a hard dental filling after being placed in a tooth.
 8. A manufacture specifically for a dentist to use in producinng hard dental fillings in a substantially uniform manner, said manufacture being composed of two paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of material to produce a dental filling to be made, the material in one of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said paste-like material; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of substantially the same premixed unpolymerized resin binder system as in said first container; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of the material in said other container; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity to produce relatively rapid polymerization of said system; the mixture of materials extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known and substantially uniform time to produce a hard dental filling after being placed in a tooth; and the quantity of material containing the activator being colored so that said mixture will substantially match the color of the tooth in which it is to be placed.
 9. A manufacture specifically for a dentist to use in producing hard dental fillings in a substantially uniform manner, said manufacture being composed of two paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of material to produce a dental filling to be made, the mateial in one of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portioN which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler selected from the group consisting of fused silica, aluminum oxide, crystalline quartz and glass beads, said filler constituting at least 65 percent by weight of said paste-like material; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of: substantially the same premixed unpolymerized resin binder system a. in said first container; finely-divided, organosilane keying agent-treated, inorganic filler selected from the group consisting of fused silica, aluminum oxide, crystalline quartz and glass beads, said filler constituting at least 65 percent by weight of the material in said other container; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity to produce relatively rapid polymerization of said system; the mixture of material extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known and substantially uniform time to produce a hard dental filling after being placed in a tooth; and the quantity of material containing the activator being colored so that said mixture will substantially match the color of the tooth in which it is to be placed.
 10. A manufacture specifically for a dentist to use in producing hard dental fillings in a substantially uniform manner, said manufacture being composed of two paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of materials to produce a dental filling to be made, the material in one of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said paste-like material, in which a small portion of said filler is replaced by an amount of hydrophobic submicron silica sufficient to substantially eliminate separation between said binder system and said filler; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of: substantially the same premixed unpolymerized resin binder system as in said first containers; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of the material in said other container in which a small portion of said filler is replaced by an amount of hydrophobic submicron silica sufficient to substantially eliminate separation between said binder system and said filler; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity of produce relatively rapid polymerization of said system, the mixture of materials extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known and substantially uniform time to produce a hard dental filling after being placed in a tooth.
 11. A manufacture specifically for a dentist to use in producing hard dental fillings in a substantially uniform manner, said manufacture being composed of two paste-like materials disposed in separate containers and from each of which containers a dentist may extract necessary amounts of material to produce a dental filling to be made, the material in One of said containers consisting essentially of: premixed unpolymerized resin binder system containing active polyfunctional monomer having a central portion which contains at least one aromatic ring and at least two acrylic end groups and in which said resin binder system includes at least 85 percent by weight of bis phenol A backbone monomer; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of said paste-like material; and free radical generating catalyst for said system in which the free radicals when generated in sufficient quantities will produce relatively rapid polymerization of said system; the material in the other of said containers consisting essentially of: substantially the same premixed unpolymerized resin binder system as in said first container; finely-divided, organosilane keying agent-treated, inorganic filler constituting at least 65 percent by weight of the material in said other container; and activator reactive with the catalyst in the material of said one container to cause generation of free radicals in sufficient quantity to produce relatively rapid polymerization of said system, the mixture of materials extracted from each of said containers causing polymerization of said binder system to be initiated and hardening of the mixture to occur in a known and substantially uniform time to produce a hard dental filling after being placed in a tooth. 